#!/usr/bin/perl
use strict;
use warnings;

use 5.010;
use Data::Dumper;

my $VERY_BIG_NUM = 2_000_000_000;

my @problem = grep { $_ !~ /^\s*#/ and $_ !~ /^\s*$/ } map { chomp; $_ } <DATA>;
die "ERROR: Problem description incomplete."
    unless(@problem >= 3);

my ($num_of_vertices, $num_of_edges) = split / /, shift @problem;
die "ERROR: Not enough vertices given."
    unless($num_of_vertices and $num_of_vertices > 1);
die "ERROR: No edge given."
    unless($num_of_edges);

die "ERROR: Number of edges not equal to declare numberd $num_of_edges of edges."
    if(@problem - 1 != $num_of_edges);

# Get the problem to solve
my ($start_vertex, $end_vertex) = split / /, pop @problem;
say "Problem with $num_of_vertices vertices and $num_of_edges edges";
say "Determine shortes path from vertex $start_vertex to $end_vertex";

# read the remaining edges
my %vertices;
my %edges;

foreach my $edge (@problem) {
    my ($start, $end) = split / /, $edge;
    $edges{$start}->{$end} = {
        'weight' => 1,
    };
    $edges{$end}->{$start} = $edges{$start}->{$end};

    foreach my $node ($start, $end) {
        $vertices{$node} = {
            'predecessor' => undef,
            'distance' => $node == $start_vertex ? 0 : $VERY_BIG_NUM,
        };
    }
}

say "Vertices: " . Dumper(\%vertices);
say "Edges: " . Dumper(\%edges);


__DATA__
5 6
1 2
2 3
2 4
4 5
1 3
3 5
1 5